The 7th Heaven star and her husband, Michael Cameron, are preparing to become parents in April (13), and Mitchell has opened up about her growing belly in a blog for People.com.
Mitchell reveals it took her a while to get used to her changing shape, but is delighted she is now able to eat dairy products after years of avoiding them.
In the blog, Mitchell writes, "I am... in awe of the body transformation. I have always been incredibly in tune with myself, but watching it truly transform and change shape has been unsettling at times. (I never knew I was vain until I watched the numbers on the scale steadily rise... I am slowly getting over this).
"My food allergies have totally disappeared - turns out baby likes yogurt, eggs, cheese ... all things I haven't eaten in years because of my inability to process them. Bring on the pizza!
"Lastly, the beauty of the belly (again, at times unsettling). The true transformation of the body - changes I could never have imagined - I can't help but find it completely magical. It is absolutely fascinating, and now even more so as I begin to feel movement and kicks (this I can totally get used to!)."
Mitchell also tells fans she is expecting a daughter, adding, "So you may or may not be wondering what this little bundle of joy is ... BOY or GIRL? Hmm ... should I tell you? Well if you twist my arm, we are thrilled to be welcoming a beautiful baby girl into our family! And yes, she has already stolen my husband's heart."